www.geogebra.org - Geogebra is completely free.
This is going to sound like a paid advertisement, but I can not begin to explain the brilliance of this program. It is so good on so many levels that it is unreal. I recently had the priveledge to attend a presentation by the author of this program, Markus Hohenwarter at the
Florida Educational Technology Conference in Orlando and was blown away.
Geogebra is completely free.
Geogebra is very similar to Geometer's Sketchpad. Unfortunately, my comparison between the programs has to end there as financial restraints have prevented me from ever being very familiar with that program. I would very much like to hear a comparison of the two programs made by someone with a lot of experience with Geometer's Sketchpad. Essentially, Geogebra it is a program for creating interactive mathematical diagrams that also include all algebraic expressions. The scope of the program is very broad, covering almost all functions and digrams covered in high school Algebra, Geometry and Calculus (I say almost only because I haven't used the program long enough to know for sure if it is lacking in any content). Additionally, Geogebra provides features geared towards promoting interaction with content. For example, sliders can be easily placed on diagrams and assigned to values.
Geogebra is completely free.
As if the mere existence of such a free powerful program was not enough, the program has been created in java making it available for use on any platform. As such, Geogebra allows the user to output diagrams as stand-alone java applets. The power of this feature is groundbreaking (yes, I know it was available in Geometer's Skethpad, but not for free). What this means is that any teacher will be able to use the program to easily create customized virtual manipulatives and interactive worksheets for their classroom. Many teachers are already doing this and contributing their content to the Geogebra wiki and user forums (see
www.geogebra.org for these and other geogebra resources). Virtual manipulatives that would take me 10-12 hours to create in Flash can literally be created in minutes by someone with no programming experience whatsoever.
Geogebra is completely free.
It is my hope to have some video tutorials for the program completed in the near future, and you will find them here when they are ready. For now you need to do 3 things. 1) Download the program and start using it. 2) Tell every math teacher you know about it. 3) Support the free mentality that the program was created on by posting your lessons to the Geogebra wiki for other teachers to use.
Did I mention that Geogebra is completely free?